Non-volatile memory is becoming standard in consumer appliances such as digital cameras, digital audio players, and personal digital assistants. The prevalence of the MS-DOS FAT file system in the personal computer space has led to a broad acceptance of this file system in the nascent consumer appliance market as well. The DOS FAT file system re-writes file system structures, such as entries in a file allocation table, when data is modified. Because the memory cells in a write-once memory device can only be written into once, the DOS FAT file system is typically not used with write-once memory devices. Instead, specially-designed write-once file systems, such as ISO9660 and Universal Disk Format (UDF), are used. Unfortunately, data stored using a write-once file system typically cannot be read by a write-many file system. This leads to an interoperability problem between write-once memory devices and host devices using a write-many file system (e.g., personal computers using the DOS FAT file system). Further, while the ISO9660 and UDF write-once file systems are appropriate for optical media, such as CD-ROMs and DVDs, they are not suitable for a semiconductor memory operating in consumer electronic devices.
There is a need, therefore, for a method for storing data in a write-once memory array using a write-many file system.